HubSpot Marketing Events Extension
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For Agents
Register external marketing events and per-attendee attendance state in HubSpot, keyed by externalEventId so a third-party event platform stays in sync with HubSpot CRM.
Use for: I need to register a webinar in HubSpot, Upsert a batch of events from our event platform, Mark a contact as ATTENDED for a HubSpot marketing event, Cancel a marketing event in HubSpot
Not supported: Does not handle email sends, marketing campaign creation, or contact list management — use for marketing event registration and attendance state only.
Jentic publishes the only available OpenAPI specification for the Marketing Events Extension, keeping it validated and agent-ready. The Marketing Events Extension API registers external marketing events such as webinars, conferences, and virtual sessions inside HubSpot. Apps create or upsert events keyed by externalEventId, search and cancel events, and record per-attendee state transitions like REGISTERED, ATTENDED, or CANCELLED. The same surface configures app-level integration settings and delivers attendance updates by either contactId or email.
Install Jentic One Beta
Connect the Marketing Events Extension to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Marketing Events Extension, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Marketing Events Extension API.
Register a marketing event by externalEventId so HubSpot tracks attendance against contact records
Upsert a batch of events to keep HubSpot in sync with an external event platform
Record per-attendee state transitions (REGISTERED, ATTENDED, CANCELLED, NO_SHOW)
Cancel or complete an event and propagate the change to attendee records
Search marketing events by name, organiser, or time window
Configure app-level integration settings for the marketing events extension
Update attendee state by email when the contact is not yet known to HubSpot
Use Cases
Patterns agents use Marketing Events Extension API for, with concrete tasks.
★ Webinar Platform Sync
Companies running webinars on Zoom, On24, or GoToWebinar push every event and attendance update into HubSpot via this API. The events upsert endpoint keeps HubSpot in sync with the event platform, and the per-state attendance endpoints record who registered and who actually attended. Marketing then segments and follows up based on attendance state.
Upsert event with externalEventId 'zoom-12345', name 'Q3 Product Launch Webinar', then call POST /marketing/v3/marketing-events/attendance/zoom-12345/ATTENDED/create with the contactIds who joined
Email-Keyed Attendance
When attendees register on a third-party platform with an email that may not yet exist in HubSpot, the email-create and email-upsert variants of the attendance endpoint accept email addresses directly. HubSpot creates or updates the contact record to match and records the attendance state in the same call, so the integration does not have to look up contacts first.
Call POST /marketing/v3/marketing-events/attendance/zoom-12345/REGISTERED/email-create with email 'jane@example.com' and joinedAt timestamp
Event Lifecycle Management
Events get postponed, cancelled, or completed and HubSpot's view needs to track each state. The cancel and complete endpoints transition the event itself, and the search endpoint helps the integration find existing events by name when an externalEventId is not known. The delete endpoint archives events that should no longer appear in marketing reports.
Search for events by name 'Product Launch Webinar', then call POST /marketing/v3/marketing-events/events/{externalEventId}/cancel for the matching event
Agent-Driven Event Registration
An AI agent that runs the company's webinar operations uses Jentic to register attendees as they sign up on a third-party platform. It searches for 'register hubspot marketing event attendee', loads the schema, and posts the attendee state transition immediately so HubSpot's segmentation always reflects the current attendee list.
Search Jentic for 'mark hubspot event attendee', load the schema, and post the REGISTERED state transition for each new sign-up
Key Endpoints
16 endpoints — jentic publishes the only available openapi specification for the marketing events extension, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
POST
/marketing/v3/marketing-events/events/upsert
Upsert a batch of marketing events
POST
/marketing/v3/marketing-events/events/search
Search marketing events
POST
/marketing/v3/marketing-events/events/{externalEventId}/cancel
Cancel an event
POST
/marketing/v3/marketing-events/events/{externalEventId}/complete
Mark an event complete
POST
/marketing/v3/marketing-events/attendance/{externalEventId}/{subscriberState}/create
Record attendee state transition by contactId
POST
/marketing/v3/marketing-events/attendance/{externalEventId}/{subscriberState}/email-create
Record attendee state transition by email
GET
/marketing/v3/marketing-events/{appId}/settings
Get app-level marketing events settings
POST
/marketing/v3/marketing-events/events/upsert
Upsert a batch of marketing events
POST
/marketing/v3/marketing-events/events/search
Search marketing events
POST
/marketing/v3/marketing-events/events/{externalEventId}/cancel
Cancel an event
POST
/marketing/v3/marketing-events/events/{externalEventId}/complete
Mark an event complete
POST
/marketing/v3/marketing-events/attendance/{externalEventId}/{subscriberState}/create
Record attendee state transition by contactId
POST
/marketing/v3/marketing-events/attendance/{externalEventId}/{subscriberState}/email-create
Record attendee state transition by email
GET
/marketing/v3/marketing-events/{appId}/settings
Get app-level marketing events settings
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
HubSpot developer hapikeys, OAuth tokens, and private app tokens are stored encrypted in the Jentic vault. Agents receive a scoped token at call time so HubSpot credentials never enter the agent's context.
Intent-based discovery
Agents search by intent (e.g., 'create hubspot marketing event') and Jentic returns POST /marketing/v3/marketing-events/events/upsert with its input schema, including externalEventId, name, and time fields.
Time to first call
Direct HubSpot integration: 2-3 days for OAuth, event schema, attendee state mapping, and reconciliation. Through Jentic: under 1 hour — search, load schema, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Marketing Events Extension API through Jentic.
Why is there no official OpenAPI spec for the Marketing Events Extension?
HubSpot does not publish an OpenAPI specification. Jentic generates and maintains this spec so that AI agents and developers can call the Marketing Events Extension via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.
What authentication does the Marketing Events Extension API use?
It accepts the developer hapikey query parameter, OAuth 2.0 access tokens, the private-app-legacy header, and the hapikey query parameter as a legacy fallback. Jentic stores all of these credential types in its encrypted vault and provides agents with scoped tokens at execution time.
Can I record attendance for a contact that does not yet exist in HubSpot?
Yes. POST /marketing/v3/marketing-events/attendance/{externalEventId}/{subscriberState}/email-create accepts an email address directly. HubSpot creates or updates the contact record to match and records the attendance state in the same call, so no separate contact lookup is required.
What are the rate limits for the Marketing Events Extension API?
Standard HubSpot API limits apply: 100 requests per 10 seconds per private app token and 110 per 10 seconds per OAuth app per portal. For high-volume webinar imports, use the events upsert batch endpoint and the email-upsert attendance variant rather than one call per attendee.
How do I register a marketing event through Jentic?
Search Jentic for 'create hubspot marketing event', load the schema for POST /marketing/v3/marketing-events/events/upsert, and execute with an array of events keyed by externalEventId. For one event at a time, POST to /marketing/v3/marketing-events/events with the event payload.
Is the Marketing Events Extension API free?
API access is included with any HubSpot subscription that has Marketing Hub features. Marketing event records appear on contact timelines and in Marketing Hub reports; reporting depth scales with the Marketing Hub subscription tier.
GET STARTED